Learn Italian: Le ripicche rovinano i legami; infatti, devi evitarle. - Spiteful acts ruin bonds; in fact, you must avoid them.

Una ripicca is a petty, spiteful act or a tit-for-tat retaliation. It's what often happens when you hold a grudge against someone (avercela con qualcuno). If you are angry at a friend (ce l'hai con un amico) and ignore their texts on purpose to get back at them, that action is una ripicca.

Does infatti mean the exact same thing as the English "in fact"?

Not exactly. While "in fact" is a good translation here, infatti is used specifically to confirm or logically follow up on the previous statement, much like "indeed" or "sure enough." If you want to use "in fact" to contradict or correct something (meaning "actually..."), you cannot use infatti; you should use in realtà or a dire il vero instead.

In evitarle, what does the le refer to, and could I put it somewhere else?

The le is the feminine plural direct object pronoun replacing le ripicche. Because it is governed by the modal verb devi, you have two choices for placement. You can attach it to the dropped '-e' of the infinitive (devi evitarle) or place it before the conjugated modal verb (le devi evitare). Both options are completely correct and mean the exact same thing.

The word legami means "bonds". What verb is this related to?